docs: update README with UI modernization, fix chat icon rendering

- Update README: KPI dashboard, SVG icon system, Chart.js, report summary endpoint, ADB wallet fix, updated file sizes
- Fix ${IC.bot} rendering literally in chat empty state (single quotes → template literal)
- Scale up chat empty state SVG icon to 48px

frontend/index.html

@@ -239,6 +239,7 @@ tbody tr:last-child td{border-bottom:none}
 /* ── Empty States ── */
 .emp{text-align:center;padding:2.5rem 1.5rem;color:var(--t4)}
 .emp .eic{font-size:2.2rem;margin-bottom:.55rem;filter:grayscale(.3)}
+.emp .eic svg{width:48px;height:48px}
 .emp p{line-height:1.55}
 
 /* ── Explorer ── */
@@ -630,7 +631,7 @@ function rPg(){switch(S.tab){case'chat':return rChat();case'terraform':return rT
 
 /* ── Chat ── */
 function rChat(){
-  const ms=S.msgs.length===0?'<div class="emp"><div class="eic">${IC.bot}</div><p>Inicie uma conversa com o agente.</p><p style="font-size:.74rem;margin-top:.35rem">Selecione um modelo para começar.</p></div>'
+  const ms=S.msgs.length===0?`<div class="emp"><div class="eic">${IC.bot}</div><p>Inicie uma conversa com o agente.</p><p style="font-size:.74rem;margin-top:.35rem">Selecione um modelo para começar.</p></div>`
     :S.msgs.map(m=>`<div class="cm cm-${m.r}"><div class="cb">${fm(m.c)}</div>${m.t?`<div class="cm-ts">${m.t}</div>`:''}</div>`).join('');
   const provs={};for(const[mid,info]of Object.entries(S.models)){const p=info.provider||'other';if(!provs[p])provs[p]=[];provs[p].push({id:mid,name:info.name})}
   const provOrder=['openai','google','meta','xai'];